1. Virtual Private Network
prepared by
Rachna Agrawal
Lixia Hou

2. Virtual Private Network (VPN)
VPNs are private data networks over public network – usually the Internet.
VPNs extend corporate networks to remote offices, mobile users, telecommuters and other extranet partners.
VPNs use advanced encryption and ‘tunneling’ technology to establish secure, end-to-end private network connections over Internet.

3. A typical VPN

4. VPN Solutions
Remote access VPNs establish secure, encrypted connections between mobile or remote users and their corporate networks via a third-party network, such as a Internet Service Provider(ISP)
- VPN client – software, hardware as well as router, or firewall based solutions available.
- Reduced cost of long distance access calls and internal equipment inventory

5. VPN Solutions
Site-to-Site VPNs are an alternative WAN infrastructure that used to connect branch offices, home offices, or business partners' sites to all or portions of a company's network.
- Intranet VPNs provide full access to company’s network
- Extranet VPNS provide business partners with limited access to a company’s network

6. VPN Technology
Trusted VPNs – companies lease circuits from communication providers and use them in the same manner they use physical cables in a private LAN
- Communication provider is ‘trusted’ for data integrity and security.
- Used before Internet became universal

7. VPN Technology
Secure VPNs use Internet as a corporate communication medium. Data is encrypted before sending, moved over to Internet, and then decrypted at the receiving end.
- Encryption creates a security ‘tunnel’ that can’t be attacked
- More desirable than Trusted VPNs

8. VPN Technology
Hybrid VPNs – A secure VPN is created as part of the trusted VPN thus creating a ‘hybrid’ VPN. Secure part of the VPN is usually administered by customer (using VPN equipments).
Secure VPNs that are administered by ISPs are called provider-provisioned VPNs.

9. VPN Building Blocks
Security is built around authentication, authorization, and accounting capabilities.
Network, data, and addresses are encrypted so they are understood by right sender and receiver only.

10. VPN Building Blocks
Quality of Service addresses two fundamental requirements – predictable performance and policy implementation
QoS capabilities allow users to prioritize service classes, manage bandwidth, and avoid congestion.
Pkt. classification based on IP address, TCP/UDP port no, IP precedence(3bits in the ToS field of IP header), MAC address, URLs & sub-URLs

11. VPN Building Blocks Management of devices – ‘simpler is better’
Element-based – less expensive. adequate for managing & monitoring small setup
Policy-based – centralized for larger networks, policies established and push them to all applicable devices
Outsource VPN management to the ISP or SASP

12. VPN Building Blocks VPNs provide reliable access to network
VPN software allows transmitted data packets to transparently switch over to a different path in case of a device failure
Redundancy in hardware components reduces the risk of downtime

13. VPN: making choices
Do-it-Yourself VPNs - four basic areas of consideration:
Internet Service
Security Policy Server
A Public Key Infrastructure (PKI) system
- VPN gateway solution

14. VPN Gateways
VPN gateways can be categorized as Standalone or Integrated.
Standalone VPNs incorporate purpose-built devices between - the source of data and WAN link OR between the modem and a data source in a remote office.
Integrated implementations add VPN functionality to existing devices such as routers, firewalls.

15. Gateway Solutions
Router based VPNs – adding encryption support to existing router(s) can keep the upgrade costs of VPN low.
Firewall based VPNs – workable solution for small networks with low traffic volume.
Software based VPNs – good solution for better understanding a VPN, software runs on existing servers and share resources with them

16. Gateway Solutions
Internet Security Devices – Standalone VPN devices specifically designed for tunneling, encryption, authentication are easier to setup and make attractive choice for business looking for ‘turn key’ solutions

17. Outsourcing Things to consider before outsourcing -
For connecting remote offices consider an ISP that also offers POP to connect to Internet as a local call
Redundancy of equipment, connections, and people
Provider policies, equipment, employee qualification to deal with outside hackers and viruses
On-site consulting assistance

18. VPN Protocols
IPSec – Internet standard protocol for tunneling. Encryption, and authentication.
Layer2Tunneling Protocol (L2TP) – Provides a means for tunneling IP traffic in layer 2, encloses non-Internet protocols i.e. IPX, SNA, and AppleTalk inside IP envelope.
Point-to-Point tunneling - proprietary Microsoft

19. Benefits of using VPN
Lower costs – remote access costs have reduced by 80 percent while LAN-to-LAN connectivity costs is reduced by percent. For companies just setting up their network VPN provides low-cost alternative to backbone equipment, in-house terminal equipment and access modems.
Connectivity Improvements – VPN based links are easy and inexpensive ways to meet changing business demands.

20. Benefits of VPN
Anywhere anytime access – ubiquitous public internet offers transparent access to central corporate systems i.e. , directories, internal-external web-sites.
VPN technology is improving rapidly and promises a bright future for data communication, its cost-effective, and high returns on investment will outweigh any skittishness in investing in new technology.